Wild Plants in the City - Arnold Arboretum - Arnoldia - Home

116 Pages·2006·4.26 MB·English

Wild Plants in the City
The curious gardens of wild greenery that penetrate cracks
in city pavement and grow lushly on old building lots are pro-
duced primarily by plants which have immigrated from over-
seas. A few of them were brought originally to North America
as garden plants and have since run wild; but most have slipped
in accidentally, their tiny seeds caught in the belongings and
supplies of settlers or mixed with the seeds of commercial crops.
Many of the most common weeds we find growing in our
cities date far enough back into man’s history to have grown
in the settlements of ancient Greece and to have marched across
Europe with the Romans. Man seems to have produced the
conditions they require to flourish, and it is largely through his
agency that they have come to assume such prominence
throughout the world. By destroying the native vegetation with
his towns and roads, fields, pastures and gardens, civilized man
has opened the way for weeds; and through his wide-ranging
travels, he has helped scatter them to every corner of the earth.
The aggressive characteristics which suit these weedy plants
so well to their role as pioneers on cleared sites are the same
traits which make them troublesome to gardeners. They are a
vigorous, adaptable and tenacious group, well-equipped to seize
a quick foothold and thrive where other plants cannot effectively
compete with them. They grow well even where soil is deficient
in nutrients; often where it is too dry or too moist, too alkaline
or too acid. They grow fast enough to surpass their struggling
rivals, and they produce unusually abundant seed crops that
are apt to fill the surrounding soil with their offspring. Their
seeds may be able to lie dormant in the soil for decades, if
necessary, until conditions are favorable for germination - and
it is suspected that some may last for centuries.
The ease with which the more common weeds have spread
from one site to another, and from one part of the world to
137

139
another, is explained largely by their enormous production of
easily dispersed seeds. Nowhere is this more apparent than
in the midst of the city, where the bare soil of new sites be-
comes settled with plants almost overnight. Where do these
seeds come from? Some, of course, already may be present in
the soil of a new lot, and merely need to be brought closer to
the surface through cultivation or bulldozing in order to ger-
minate. Other seeds are carried into a new site with the fill
used to cover the foundation of a demolished building, or in
the topsoil of a landscape planting. Still others, such as the
seeds of Poplar, Dandelion and Milkweed, are equipped with
silky parachutes which allow them to float on wind currents
from surprisingly long distances. Heavier seeds are dropped by
nearby trees, and seeds contained within edible fruits and
berries often are scattered by feeding birds and animals. Seeds
also are transported on fur and clothing, in mud on the soles of
shoes, and on the wheels of vehicles.
This continual invasion of seeds helps explain the speed with
which weeds can colonize a bare site, even when there are few
other plants in view. Within a year a vacant lot’s cleared surface
may be covered with plants, and within two years tree saplings
may be evident. Within three or four years, an undisturbed lot
will be wildly overgrown.
But few lots have an opportunity to actually reforest them-
selves, for the wild gardens that occupy these areas in the city
tend to have a fleeting life. Few are left completely undisturbed
for more than two or three years, and they often are replaced
so rapidly with one of man’s constructions - an asphalted
parking lot, a used car lot - that the transformation can be
somewhat startling to observers.
The role of these wild plants in the city is an especially am-
biguous one. Their presence is often a mark of neglect and
poor land management, yet the spontaneous cover they provide
is a welcome improvement over the rubble-strewn and dusty
wastelands which otherwise would be in view. They raise ques-
tions about the use and management of vacant land in the city,
for when land is so precious, one wonders how these "waste-
lands" can be economically and socially expedient.
This is a rather typical building lot, slightly on the seamy side, but
already lushly carpeted with Clover and Mugwort (and a less typical
Grass) after a few years of growth. The trees springing up along
the foundations of adjacent buildings are saplings of the Tree of
Heaven.
140
Despite its untidyness, the wild plant growth on these lots
has many delightful qualities. Even the seamiest site conveys
an intriguing sense of life and a connection with nature that
is often lacking in the simplistic environments of contemporary
parks and playgrounds. It offers the diversity of an entire com-
munity of plants and insects; a surface that has contours, slopes
and hollows; and the pleasant surprise of new perspectives and
contrasts: the wild lushness of a weedy planter set against the
elegance of Copley Square, sheer cliffs rising against the Boston
skyline, or an unexpected puddle of water surrounded by Cat-
tails and Sedges.
A Note on Trees and Shrubs
In contrast to the vast number of foreign flowers and grasses
which were introduced accidentally into the United States and
now grow wild in New England towns, the trees and shrubs
one is apt to encounter growing wild here are either native
plants or plants which were intentionally brought here for cul-
tivation.
On the following pages we have provided only a small sam-
pling of these woody plants; there are many others which most
certainly will be encountered as well - such as the Apple, Ca-
talpa, Horsechestnut, Mulberry, and Linden. Exactly what one
finds in a particular area depends, of course, on what has been
planted there. For instance, the large number of volunteer Ma-
ples, Oaks, and Elms which spring up in Boston may be at-
tributed to the use of such trees for street plantings. The poten-
tially large number of other trees and shrubs which may appear,
depending on the breadth of local plantings, is suggested by
the wide variety of exotic seedlings one finds growing on the
Arnold Arboretum grounds and within a few miles of its
boundaries.
One group of plants is notably absent in the city, however,
and this is the evergreens. Nowhere in urban Boston have we
seen seedlings of such evergreens as the Pines or Junipers,
which are such prominent pioneers of the old fields in more
rural areas.
This is one of a series of tiny ponds we found hidden among piles of
fill which had been dumped systematically across a lot along South
Huntzzzgton Avenue. One day we came upon two wild duchs floating
in the center of this pond, on another occasion we flushed a pheasant
out of the surrounding vegetation. Wildlife may be more plentiful on
this lot than most others because of its proximity to the Muddy River.
On the pond’s edges grow Willows, Cat-tails, Sedges, and - in mid-
summer - a bright array of wildflowers, such as Loosestrzfe, Tansy,
and Queen Anne’s Lace.

From the road this waterfront area looks like an abandoned parking
lot; but as one approaches the back of the site, small ponds (such as
this one rimmed by Cat-tails and beautiful Grasses) appear in shal-
low depressions.
A miniature meadow, created by a weedy planter in Copley Square,
stands in strange juxtaposition to the urban surroundings. The planter
was dominated by Clover, Yellow Wood Sorrel, and Horseweed, but
we collected 30 different kinds of plants from this site. Shortly after
this photograph was taken, the weeds were removed and a cover of
sod laid down, producing a neater, but less interesting, landscape.
143
These spectacular cliffs are one of the finest natural features of Boston
now in private hands, and they should be carefully preserved. They
form an outcrop along one side of Mission Hill, hnown as "The Ledge."
Looking across the old quarry which lies on one side of The Ledge,
one sees the startling juxtaposition of natural and man-made land-
scapes pictured at right.
144
In the quarry grow trees of many kinds, such as the Tree of Heaven,
Norway and Sycamore Maples, Black Locust, Oaks, Poplars, and Ashes.
Pin Oaks and Gray Birches (and even occasaonaL ferns) grow out of
the crevices in the cliffs. On the rim above the cliffs are a few Black
Cherries, a Red Maple or two, and a large, rather flat field covered
with flowers of many different kinds.
145